Control apparatus



United States Patent C 2,915,651 CONTROL APPARATUS Arnold J. Samuels,Forest Hills, and Irving Yamet,

Riverdale, N.Y.

Application February 27, 1957, Serial No. 642,860 2 Claims. (Cl.307-415) The present invention relates to a control circuit primarilyintended for use with power presses, brakes, shearing machines, andother automatic and semi-automatic equipment. 7

In the operation of presses, shears and other types of machines, thereis considerable danger to the hands of the operator. There are'knowncircuits and arrangements of parts which have been proposed to solvethis problem wherein the cycle of the machine is initiated by theclosure of two safety switches spaced apart sufliciently to precludeoperation of both by one hand. Such r prior art proposals have however,lacked the extreme versatility of the present invention.

There are also devices in the prior art embodying control circuits forvalves or switches, for example, which in turn control the operation ofthe machine itself. Such control circuits may incorporate a switch,closed by movement of amachine part, to energize a holding circuit whichin turn deenergizes a circuit containing the main control valve orswitch. These devices however, are not of the fail-safe type, in thatthey do not provide for the interruption of the main control circuitshould the switch itself be dislodged from the machine, or its normalfunctioning otherwise disrupted.

Another common deficiency of known equipment of this type is that itpermits an operator to close the safety switches to initiate a cycle,then release them during the hand movable contact 23 of a relay 24. Inthe unenergized condition of the relay 24 as depicted, its contact 23engages an upper right-hand contact 26, which is connected through aconductor 27 to one terminal of a socket 78 mounted on a wall of thehousing 12. Another terminal of the socket 78 is connected by aconductor 28 to a conductor 29 which extends from a lower terminal ofthe switch 22 to a terminal of another socket 31 supported by one of thehousing walls.

A conductor 32 connects the conductor 29 to the lefthand movable contact33 of a relay 34, depicted as unenergized. Upon energization of therelay 34, the contact 33 will move downwardly into engagement with thelower left-hand contact 36, which is connected by a conductor 37 to theleft-hand movable contact 38 of a relay 39, depicted as unenergized.Upon energization of the relay 39, its contact 38 will engage the lowerlefthand contact 41, which is connected by a conductor 42 to theleft-hand movable contact 43 of a relay 44, likewise depicted asunenergized. Again, upon energization of the relay 44, its contact 43will engage the lower lefthand contact 46 which is connected by aconductor 47 to one side of the Winding of a motor, such as anelectromagnetic motor or solenoid valve 48 which energizes the machine,as by admitting fluid under pressure to an operating cylinder, or bysome equivalent arrangement which will cause the machine to commence itscycle of cycle, and finally reclose them near the end of the cycle tocause a second cycle to be commenced, thus exposing the work to damageand the operator himself to unnecessary danger.

. It is among the objects of the present invention to provide a controlcircuit which may be readily installed on a conventional machine withoutrequiring redesign or substantial modification; to provide a safetycontrol circuit of the fail-safe type; and to provide a safety controlcircuit rendering it impossible for the operator to initiate a new cycleprior to the conclusion of an existing cycle.

A more complete understanding of the invention will follow from adescription of the accompanying drawing wherein the single figureillustrates the circuit according a suitable housing 12 generallyindicated by broken lines.

One of these leads 10 is connected through a fuse 13 to one pole of amain switch 14 whose second pole is connected to a conductor 16 leadingto one terminal of the primary winding 17 of a step-down transformer 18,having a secondary winding 19. Apilot lamp 15 is connected to the secondpole of the main switch 14 and by a conductor 20 with supply lead 11 toindicate when the switch 14 is closed. The conductor 16 is alsoconnected ,-with a conductor 21 which interconnects a central terminalof three-pole double throw switch 22 and the right operation. The otherside of the winding of the motor 48 is connected by a conductor 49 tothe supply lead 11. A .conductor 51 connects one side of the transformersecondary 19 with the right-hand side of the winding of the relay 24;the conductor 51 also joins a conductor 52 connected in parallel withone terminal of a socket 53 and a conductor 54 which leads to the fixedterminals of each of a plurality of sockets 56, 58 and 61, producing aparallel connection of these terminals with the aid of conductors 57 and59. Removable operating switches 62, 63 and 64 of the plug-in type aredepicted as received by the sockets 56, 58 and 61, respectively. Two ofthese operating switches may be safety switches of known types,positioned in spaced relationship so as to insure that an operators handis not in the path of any moving parts of. the machine when it isoperated. The third or any additional number of operating switches mayserve as positioning switches controlled by the work to assure properpositioning relative to the operating parts of the machine, such as apress or shear. In applications not requiring the safety features, anyor all of the operating switches can serve to facilitate production. Forexample, one or more such switches can be actuated by properly locatingthe work in a die. When this occurs and all other operating switchesthen in circuit are closed, one cycle of operation of the machine willoccur. After all of the operating switches have been opened and againclosed, a subsequent cycle of operation can be effected.

The second terminal of each of the sockets 56, 58 and 61 is connected tothe winding of its corresponding relay 44, 39 and 34 by means ofconductors 66, 67 and 68", respectively. The other sides of the windingsof the relays 44, 39 and 34 are connected in parallel by conductors 69,71 and 72 to the upper right-hand terminal of the switch 22, engagingthe central right-hand terminal, in the position shown, through switch22 when in the position shown to conductor 73 and connected by means ofthe same conductor 73 to the other side of the trans former secondary19. The conductor 69 is also connected with the lower right-hand contactof the relay 44.

nected by a lead 79 to the conductor 73. These terminals of the socket78 are connected by conductors 81 and 82 to a lower pair of terminals ofa double make double break switch 83 whose movable contact is biaseddownwardly by means of a compression spring. The upper pair of terminalsof the socket 78 are connected by means of leads 8'1 and 82' to theupper fixed contacts respectively of the switch 83. An operator 84attached to the movable contact is disposed in the path of a movablepart 86 of the machine to be controlled. The switch 83 is shown asmounted on a fixed part 87 of the machine. In the positions of theseparts as depicted, the moving part 86 is in its uppermost position oftravel, and upper contacts of the switch 83 are closed while its lowercontacts are open. When the cycle of operation begins, the moving member86 moves downwardly, whereupon the upper contacts of the switch 83 willopen and its lower contacts will close. Similarly, should the switch 83be dislodged from its position, its upper contacts will be opened andits lower ones will close. providing a safety feature not previouslyknown in such an environment.

The relay 24 has a left-hand movable contact 87 which is connected by aconductor 88 to the central movable terminal of the switch 22, whoseupper fixed terminal is connected by a conductor 89 in parallel with thecentral right-hand terminals 92, 95 and 96 of relays 44, 39, and 34,through leads 91, 93 and 94, all respectively. The relays 34, 39 and 44have their lower right contacts 97, 98 and 99 respectively, connected inparallel by means of conductors 101 and 102 to the conductor 69.

The lower right-hand contact 103 of relay 24 is connected by a conductor184 with one terminal of ,a housin supported socket 106, whose otherterminal is connected to the supply lead 11 by means of a conductor 107.This socket 106 is intended to be connected with a counter. Similarly,the socket 53, whose second terminal is connected to the conductor 76 bya conductor 183 may also energize a counter.

Comparable with the socket 31 disposed adjacent to thesocket 61, sockets109 and 111 are provided adjacent to the sockets 58 and 56 respectively.As previously stated, the conductor 29 is connected to one terminal ofthe socket 31, its other terminal being connected by a conductor 112 toa conductor 113 which extends from one terminal of the socket 109 to theconductor 37 interconnecting contacts 36 and 38 or" relays 34 and 39respectively. The other terminal of the socket .109.is connected by aconductor 114 ,to a conductor 116 which connects one terminal of thesocket 111 with the conductor 42 interconnecting contacts 41 and 43 ofrelays 39 and 44 respectively. The other terminal of the socket 111isconnected to the conductor 47 by means of acouductor117.

Plugs 118 are provided for insertion into sockets 61, 31; 58, 109; and56, 111; only one such plug having been illustrated. Eachplug 118has afirst pair of prongs 119, insulated from one another, for reception bythe sockets 61,58, and 56; and a second pair of prongs 121, which areelectrically interconnected, for shorting the terminals of the sockets31, 169, and 111. When the plugs 118 are to be used, the terminals oftheswitches 62, 63, 64 must first be removed from the sockets.

in operation, .upon closing the switch 14, a circuit will be completedfrom the supply lead 10, through conductor 16, primary 17 of transformer18 andto supply lead 13.. A circuit will also becompleted from the:supply leads through the pilot lamp 15 and the conductor 20'.Uponclosing of the switches 62, 63 and 64i, curre nt will flow from thesecondary .19 of transformer 18, through conductors 5.1, '2 and 54, andthrough conductors 66, .67, and 68, the windings of relays 44, 39 534,conductor .69, through switch .22, and conductor 73 to the other side ofthe secondary winding 19. Under these conditions the central contacts ofthe relays 34, 39 and 44 will be shifted downwardly to separate fromtheir upper contacts and engage the lower ones.

When relays 34, 39, 44 have been energized, a circuit is establishedfrom the supply lead 10 through the switch 14, conductors 16 and 21, theright movable contact 23 of the relay 24, the right upper contact 26,conductors 27, 81', the upper contacts of switch 83, conductors 82', 28,29 and 32, contacts 33 and 36 of relay 34, conductor 37, contacts 38 and41 of relay 39, conductor 42, contacts 43 and 4-6 of relay 44, conductor47, the winding of solenoid valve 48, conductor 49 and supply lead 11.

It will thus be understood that only by closing all of the switches 62,63, 64, the relays 34, 39 and 44 will be energized permitting current tobe supplied to the winding of the solenoid valve 48. Energization of thewinding of solenoid valve 48 causes the press or other machine to beginits cycle of movement, thus causing the movable machine part 86 todepart downwardly from the .fixed machine part 87. This movement resultsin opening the upper contacts and closing the lower contacts of ,theswitch 83 under the biasing action of its spring. Opening of the uppercontacts of the switch 83 opens the circuit previously described anddeenergizes the solenoid valve 48. Closure of the lower contacts of theswitch 83 completes a circuit from the secondary 19 through conductors51 and 52, the winding of relay 24, conductors 74, '76, 81, lowercontacts of switch 83, andconductors 82, 79 and 73 back to the otherside of the secondary 19. Since such energization of the relay 91, 93and 94, contacts 9697, 98, and92-99,

conductors 101, 162, 69, switch 22, and conductor 73 to the other sideof secondary 19. This holding circuit maintains relay 24 energized solong as any one of ,switches 62, 63 or 64 is closed, and hence keepsopen the circuit which includes solenoid valve 48. This insures thateach of switches 62, 63, 64 must be opened before a circuit may again becompleted through solenoid valve 48.

Due to the fact that the upper contacts of the switch 83 are normallyopen and its lower contacts normally closed during an operating cycle ofthe machine andwill be so positioned under the bias of its spring shouldthe switch be dislodged from the machine, or its normal functioningotherwise disrupted, a fail-safe arrangement is provided. Suchmalfunctioning will cause the upper contacts to open the circuit of thesolenoid valve 48 as already described. Closure of the lower contactsprovides further assurance of safety in that such closure efiectscompletion of a circuitthrough the winding of relay 24, and thus causesthe main control circuit which includes the solenoid valve 43 to beopen, as the contacts 23 and 26 or" relay 24 will be separated. It willfollow that should the cable containing conductors 81, 82, 81 and 82'become severed, as has been known to occur in practice, the effect wouldbe the same as opening the circuit of the upper contacts of the switch83.

it is extremely important in accordance with the present invention, thatin, normal operation, once the cycle has beeninitiated so that the uppercontacts of the switch 83 havebeen opened and its lower contacts closed,it is not possible 'for an operator to initiate the new cycle of thernachine prior tothe completion of the existing cycle and receive apulseeach time the relay 24 is energized.

In some instances, it may be desirable to utilize less than all of theswitches 62, 63, 64. Under such conditions, the switch or switches to beeliminated will be disconnected from their respective sockets andreplaced by a plug or plugs 118. Since the prongs 119 of the plug 118are not electrically connected, the circuit formerly completed through aswitch 62, 63, or 64 and the winding of its relay is not completed andthe relay will not be energized. However, since the prongs 121 of eachplug 118 are electrically connected, assuming a plug 118 has beeninserted in the sockets 6131, a circuit is completed from supply lead10, switch 14, conductors 16 and 21, contacts 23 and 26 of relay 24,conductors 27, 28, 29, socket 31, prongs 121, conductors 112, 113 and37, left movable contact 38 of relay 39 so as to supply current to thecontact 41 upon energization of the relay 39. Hence, although relay 34will not be energized, closing of switches 63 and 62 will energizerelays 39, 44 to permit current flow through the relay contacts, to thewinding of the solenoid valve 48, and back to the supply lead 11.Insertion of a plug 118 into sockets 59109 and/or 56111 may also beefiected.

Where it is desired that the machine operate continuously rather than bysingle strokes, the switch 22 is thrown to its other position. This willcomplete a circuit from the supply lead 10, through switch 14,conductors 16, 21, switch 22, conductor 29, prongs 121 in socket 31,conductor 113, prongs 121 in socket 109, conductors 114 and 116, prongs121 in socket 111, conductors 117, and 47, winding of solenoid valve 48,and conductor 49, to supply lead 11. Thus, there will be no interruptionof current supplied to the winding of the solenoid valve 48, as in theother position of the switch. Under these conditions however, relay 24will continue to operate and supply pulses to sockets 106 and 53 foractuating counters or auxiliary equipment if desired.

It will be understood that within the scope of the appended claimsvariations from the form of the invention described will not depart fromthe spirit of the invention.

What is claimed is:

1. In a control for a cyclically operable machine, an electromagnetenergizable to activate said machine, an energizing circuit for saidelectromagnet comprising switch means, electromotive means for openingsaid switch means upon energization thereof, energizing circuit meansfor said electromotive means including spring biased normally closedswitch means, means operable by the machine during the last part of itscycle to open said normally closed switch means, a plurality ofelectromotive means connected in parallel with each other and with saidfirst mentioned electromotive means, switch means in series with each ofsaid plurality of electromotive means, a plurality of normally openswitches each operable by one of said plurality of electromotive means,a socket, said plurality of normally open switches being connected inseries in said energizing circuit, and a bypass circuit for at least oneof said plurality of normally open energizing circuit switchescomprising a conductor leading from a part of said energizing circuit toone terminal of said socket, a second conductor leading from the otherterminal of said socket to the conductor connecting one of said normallyopen energizing circuit switches with the next, and a plug adapted to beinserted in said socket and connect said conductors.

2. In a control for a cyclically operable device having a member movablein a work cycle: a first circuit having one winding of a transformertherein; a second circuit in parallel with said first circuit comprisinga pair of normally closed contacts and a plurality of pairs of normallyopen contacts, said contacts being in series, and an electromagnet inseries with said contacts; a third circuit comprising another winding ofsaid transformer, a relay 9. spring biased normally closed switch meansoperable by the machine during the last part of its cycle to open saidnormally closed switch; a fourth circuit in parallel with said thirdcircuit comprising a plurality of relays connected in parallel and eachhaving a switch in series therewith; said relays of said fourth circuiteach carrying a pair of the normally open contacts of said secondcircuit and said relay of said third circuit carrying said pair ofnormally closed contacts of said second circuit; a fifth circuit inseries with the relay of said third circuit and comprising a pair ofnormally open contacts carried by said last mentioned relay and aplurality of pairs of normally open contacts in parallel with each otherand in series with said last mentioned pair of contacts, each of saidplurality of pairs of normally open contacts of said fifth circuit beingcarried by one of the relays of said fourth circuit; and sixth andseventh circuits in series with one another and each of which is inparallel with a pair of said normally open contacts of said secondcircuit, each of said sixth and seventh circuits comprising a socketadapted to receive a plug to close said sixth and seventh circuits.

References Cited in the file of this patent UNITED STATES PATENTS2,302,838 Bundy Nov. 24, 1942 2,404,980 Munschauer July 30, 19462,473,683 Hines June 21, 1949 2,496,574 Boger Feb. 7, 1950 2,802,154Bonn et a1. Aug. 6, 1957

